Vibratory alerts in a wrist worn alerting device are useful in providing the user with an alert indication without a disturbing audio interruption. Such a wrist worn alerting device includes a wrist worn pager.
Conventional vibratory alerting devices have limitations which make them undesirable for use in wrist worn pagers. For example, the size of a motor necessary to drive a rotating eccentric weight vibrator is often too large to be placed in a wrist worn pager. Additionally, the current drawn by such a motor is often too great for the types of miniature batteries available for a wrist worn device.
A resonant vibrator which has a cantilevered structure supporting a vibrating mass may fit better within a wrist worn pager. Such devices include piezoelectric vibrators. However, such devices induce a pulsating current on the miniature battery powering the device, the pulsating current can cause battery voltage surges which can cause other circuits in the wrist worn pager to malfunction. Additionally, the vibrational sensation experienced by the user of such wrist worn devices may not provide enough sensation for the user to detect the alert.
Thus, what is needed is a miniature vibratory alerting device having a substantially constant current drain and an improved vibrational sensation.